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- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
The OE Match Engine Cylinder Head Inlet Valve is a high-quality replacement valvetrain component designed to regulate the flow of air and fuel into the engine's combustion chamber. Manufactured to OE specifications for fit, precision and durability, this inlet valve is essential for maintaining efficient engine breathing, combustion performance and long-term engine reliability.
Sold Each.
X12 Required Per Car.
Fits:
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster 987 2.7L 2005-08/08
Diagram Ref No 8
Produced from premium-grade, heat-resistant materials, the inlet valve is engineered to withstand the constant mechanical loads and high operating temperatures associated with modern engine operation. Working in conjunction with the camshaft, valve springs, valve guides and cylinder head assembly, it ensures precise control of intake airflow, helping the engine deliver optimal power, fuel efficiency and responsiveness.
What This Product Does:
- Controls the intake of air and fuel into the combustion chamber.
- Opens and closes in precise timing with engine operation.
- Maintains an effective seal during compression and combustion cycles.
- Supports efficient airflow and engine breathing.
- Helps maximise engine performance and throttle response.
- Contributes to fuel efficiency and emissions control.
- Forms a critical part of the engine valvetrain system.
Symptoms Of Wear Or Failure:
- Loss of engine power and performance.
- Rough idle or uneven engine running.
- Engine misfires.
- Poor throttle response and acceleration.
- Increased fuel consumption.
- Low compression in the affected cylinder.
- Difficulty starting the engine.
- Ticking or tapping noises from the cylinder head.
- Engine management warning lights or fault codes.
- Failed compression or leak-down test results.
Why Replacement Matters:
- Inlet valves are subjected to continuous opening and closing cycles while being exposed to heat, combustion by-products and airflow turbulence. Over time, valves can become worn, bent, burnt, carbon-contaminated or develop sealing issues that negatively affect engine efficiency and performance.
- A damaged inlet valve can restrict airflow into the combustion chamber, resulting in poor combustion, reduced power output and increased fuel consumption. If left unresolved, valve-related problems can contribute to compression loss and may cause additional wear to valve seats, cylinder heads and other internal engine components.
- Replacing a worn or damaged inlet valve restores proper airflow, improves combustion efficiency and helps maintain optimal engine performance. An OE Match replacement provides factory-style fitment, precision manufacturing and long-term durability, ensuring reliable operation and helping protect your Porsche engine from premature wear and costly repairs.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99610511105
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
Valve Spring
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The Porsche Valve Spring is a critical component
of the valve train system fitted to numerous Porsche 911 and Porsche 964 models
from 1965 to 1994. Designed to maintain precise valve operation throughout the
engine's RPM range, the valve spring ensures that intake and exhaust valves
close correctly after being opened by the camshaft.
Fits:
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
Diagram Ref No 13
In Porsche's legendary air-cooled flat-six engines, accurate valve control is essential for maintaining combustion efficiency, engine performance, reliability, and long-term durability. The valve spring works continuously under extreme mechanical stress, cycling thousands of times per minute to keep the valve train operating correctly.
Whether you're rebuilding a classic Porsche engine, restoring a 911, or carrying out a cylinder head overhaul, replacing worn valve springs helps maintain factory performance and reduces the risk of costly engine damage.
What Does the Valve Spring Do?
The valve spring is responsible for returning the intake and exhaust valves to their closed position after each opening cycle generated by the camshaft.
Its key functions include:
- Maintaining correct valve timing operation
- Ensuring valves close fully and consistently
- Keeping the valve train under proper tension
- Preventing valve float at higher engine speeds
- Supporting engine compression and combustion efficiency
- Protecting the valve train from instability and excessive wear
Without adequate spring tension, valves may not close correctly, leading to poor performance and potential engine damage.
Why Does the Valve Spring Fail?
Valve springs are constantly subjected to compression, heat, vibration, and high engine speeds. Over time, these factors can lead to material fatigue and a gradual loss of spring tension.
Common causes of valve spring failure include:
- Metal fatigue from repeated cycling
- High mileage wear
- Prolonged exposure to engine heat
- Over-revving the engine
- Corrosion or contamination
- Performance modifications increasing valve train loads
- Age-related weakening of spring material
- Improper engine assembly or valve train geometry
As spring pressure decreases, valve control becomes less precise, particularly at higher RPM.
Common Symptoms of Worn Valve Springs
A weakened or damaged valve spring may cause:
- Loss of engine performance
- Valve float at higher RPM
- Rough idle
- Engine misfires
- Increased valve train noise
- Reduced power output Inconsistent compression readings
- Premature wear of valves, guides, and camshaft components
In severe cases, a broken valve spring can result in valve-to-piston contact and major engine damage.
When Should You Replace Valve Springs?
Valve springs should be inspected whenever the cylinder heads are removed and replaced if any signs of fatigue or wear are detected.
Replacement is strongly recommended:
- During complete engine rebuilds
- During cylinder head refurbishment
- On high-mileage engines
- When installing performance camshafts
- If valve float is present
- When spring tension falls below specification
- During preventative maintenance on restoration projects
- Whenever a spring shows signs of corrosion or damage
Many experienced Porsche engine builders replace all valve springs during rebuilds to ensure consistent valve train performance and long-term reliability.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110590151
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
This is the standard valve guide used in early air-cooled Porsche 911/930 cylinder heads. It’s a plain (non-hydraulic) guide that locates the valve stem in the head; when worn it causes oil burning, loss of compression and poor valve seating — so they’re commonly replaced whenever heads are rebuilt
- Fits:
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
Diagram Ref No 2 and 2A.
What the part is (technical data / dimensions)
Application:
Porsche 911 / 930 from about 1965–1989 (varies slightly by model and year; early cars both intake & exhaust, later years sometimes exhaust only).
Standard size (typical OE): ID ≈ 9.00 mm, OD ≈ 13.06 mm, length ≈ 51.2 mm.
Why these guides should be replaced
- Valve guides are a wearing item. Replace them when any of the following occur or when you rebuild the engine head.
- Excessive valve stem play — worn guide ID internal diameter lets the valve rock and misalign with the seat , poor sealing, reduced compression and power.
- Oil consumption / smoking — worn guides allow oil to wick down the stem into the combustion chamber, causing blue/grey smoke and fouled plugs.
- Hard starting, rough idle, misfire — poor sealing / valve timing irregularities from misaligned valves.
- Valve wobble that leads to premature valve stem wear or valve seat damage — once stems or seats are damaged you need deeper surgery.
- If a guide is cracked, broken, or has excessive ovality — must be replaced.
- Whenever you remove and refinish seats / replace springs / do a full head rebuild — replacing guides at that time is cheap insurance and ensures correct alignment.
Inner diameter 9,00 mm
Outer diameter 13,06 mm
Total Length 51,20 mm
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
93010432100
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) RS 3.6L 1991-93
- Porsche 964 (911) RS 3.8L 1991-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 924S 2.5L 1986-87
- Porsche 924S 2.5L 1988
- Porsche 944 2.5L 8V 1982-87
- Porsche 944 2.7L 8V 1988-89
- Porsche 944S 2.5L 16V 1987-88
- Porsche 944S2 3.0L 16V 1989-91
- Porsche 944 Turbo 2.5L 8V 1985-88
- Porsche 944 Turbo 2.5L 8V 1989-91
- Porsche 944 Turbo S 2.5L 8V 1988
- Porsche 928 4.5L 1978-82
- Porsche 928S 4.7L 1981-83
- Porsche 928S2 4.7L 1984-86
EACH
Fits:
Porsche 911 1968-89 (12 Per Engine)
Porsche 924S (8 Per Engine)
Porsche 944 (8 Per Engine)
Porsche 944 2.7L (8 Per Engine)
Porsche 964 3.6L (12 Per Engine)
Porsche 964 Turbo (12 Per Engine)
Porsche 928 (16 Per Engine)
Click 'Zoom in' for large parts diagram.
Diagram Ref No 19.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96410411107
The product you are viewing cross references to these numbers